RESUMEN
PURPOSE: To extract radiomic features from coronary artery calcium (CAC) on CT images and to determine whether this approach could improve the ability to identify individuals at risk for a composite endpoint of clinical events. MATERIALS AND METHODS: Participants from the Offspring and Third Generation cohorts of the community-based Framingham Heart Study underwent noncontrast cardiac CT (2002-2005) and were followed for more than a median of 9.1 years for composite major events. A total of 624 participants with CAC Agatston score (AS) of greater than 0 and good or excellent CT image quality were included for manual CAC segmentation and extraction of a predefined set of radiomic features reflecting intensity, shape, and texture. In a discovery cohort (n = 318), machine learning was used to select the 20 most informative and nonredundant CAC radiomic features, classify features predicting events, and define a radiomic-based score (RS). Performance of the RS was tested independently for the prediction of events in a validation cohort (n = 306). RESULTS: The RS had a median value of 0.08 (interquartile range, 0.007-0.71) and a weak and modest correlation with Framingham risk score (FRS) (r = 0.2) and AS (r = 0.39), respectively. The continuous RS unadjusted, adjusted for age and sex, FRS, AS, and FRS plus AS were significantly associated with events (hazard ratio [HR] = 2.2, P < .001; HR = 1.8, P = .002; HR = 2.0, P < .001; HR = 1.7, P = .02; and HR = 1.8, P = .01, respectively). In participants with AS of less than 300, RS association with events remained significant when unadjusted and adjusted for age and sex, FRS, AS, and FRS plus AS (HR = 2.4, 2.8, 2.8, 2.3, and 2.6; P < .001, respectively). In the same subgroup of participants, adding the RS to AS resulted in a significant improvement in the discriminatory ability for events as compared with the AS (area under the receiver operating curve: 0.80 vs 0.68, respectively; P = .03). CONCLUSION: A radiomic-based score, including the complex properties of CAC, may constitute an imaging biomarker to be further developed to identify individuals at risk for major adverse cardiovascular events in a community-based cohort. Supplemental material is available for this article. © RSNA, 2020.
RESUMEN
Evidence for cardioprotective effects of lycopene is inconsistent. Studies of circulating lycopene generally report inverse associations with CVD risk, but studies based on lycopene intake do not. The failure of dietary studies to support the findings based on biomarkers may be due in part to misclassification of lycopene intakes. To address this potential misclassification, we used repeated measures of intake obtained over 10 years to characterise the relationship between lycopene intake and the incidence of CVD (n 314), CHD (n 171) and stroke (n 99) in the Framingham Offspring Study. Hazard ratios (HR) for incident outcomes were derived from Cox proportional hazards regression models using logarithmically transformed lycopene intake adjusted for CVD risk factors and correlates of lycopene intake. HR were interpreted as the increased risk for a 2·7-fold difference in lycopene intake, a difference approximately equal to its interquartile range. Using an average of three intake measures with a 9-year follow-up, lycopene intake was inversely associated with CVD incidence (HR 0·83, 95% CI 0·70, 0·98). Using an average of two intake measures and 11 years of follow-up, lycopene intake was inversely associated with CHD incidence (HR 0·74, 95% CI 0·58, 0·94). Lycopene intake was unrelated to stroke incidence. The present study of lycopene intake and CVD provides supporting evidence for an inverse association between lycopene and CVD risk; however, additional research is needed to determine whether lycopene or other components of tomatoes, the major dietary source of lycopene, are responsible for the observed association.